Speed reducing bearing arrangement for a mechanically erected vertical gyro

ABSTRACT

A speed reducing bearing arrangement of the type including a dual bearing having a common race and separate complementing races and balls so selected that the contact angle of one complement of inner and outer race is different than the contact angle of the other complement of inner and outer race is used for coupling an erection mechanism for a mechanically erected vertical gyro to the gyro rotor for rotating the erection mechanism in the same direction as the rotor but at a greatly reduced speed.

United States Patent 91 Hurlburt 51 Apr. 17, 1973 1 1 SPEED REDUCINGBEARING ARRANGEMENT FOR A MECHANICALLY ERECTED VERTICAL GYRO [75]Inventor: Charles E. Hurlburt, River Edge,

[73] Assignee: The Bendix C0rporati0n,Teterboro,

[22] Filed: June 10, 1971 [21] Appl. No.: 151,655

[52] US. Cl. ..74/5.4l, 74/5, 308/183 [51] Int. Cl. ..G01c 19/30 [58]Field of Search ..74/5.41, 5.47, 5,

[56] References Cited UNITED STATES PATENTS 3,336,811 8/1967 Klemes etal ..74/5 3,336,810 8/1967 Schaffer et a1. 3,269,194 8/1966 Buckley..74/5 2,603,094 7/1952 Wrigley ..74/5 47 3,225,606 12/1965 Stiles.......308/183 X 2,577,942 12/1951 Agins 1 ..74/5 2,979,367 4/1961 Mims eta1. 10/90 X 3,547,503 12/1970 Konet ..308/l83 FOREIGN PATENTS ORAPPLICATIONS 445,974 l/l948 Canada .,74/5.41 1,183,868 3/1970 GreatBritain ..308/183 Primary ExaminerManuel A. Antonakas A!t0rneyP1ante,Hartz, Smith & Thompson 1 5 7] ABSTRACT A speed reducing bearingarrangement of the type including a dual bearing having a common raceand separate complementing races and balls so selected that the contactangle of one complement of inner and outer race is different than thecontact angle of the other complement of inner and outer race is usedfor coupling an erection mechanism for a mechanically erected verticalgyro to the gyro rotor for rotating the erection mechanism in the samedirection as the rotor but at a greatly reduced speed.

3 Claims, 3 Drawing Figures PAIENTEB APR 1 7 I973 M m m m a. n 4 5 w 4 nF \M .16. a a 4 I. a a 5 a :w

0 w QEE Swim Sago BALL CONTACT ANGLE (DEGREES) FIG. 2

FIG. 3

INVENTOR. CHA RL E5 E. .HU/PL BURT 4%, m- 14 T'TOIQIVE Y SPEED REDUCINGBEARING ARRANGEMENT FOR A MECHANICALLY ERECTED VERTICAL GYRO BACKGROUNDOF THE INVENTION 1. Field of the Invention This invention relates tospeed reducing arrangements and more particularly, to ball bearing speedreducing arrangements for use with mechanically erected vertical gyros..

2. Description of the Prior Art A mechanically erected vertical gyrocommonly utilizes some means of rotating shifting masses, or rollingballs, around the gyro spin axis at a rotational speed which is a smallfraction of the rotational speed of the gyro rotor. Prior to the presentinvention the reduction in speed has been accomplished by directreduction gearing between the gyro rotor and the rotating erectionmechanism, or by a loosely coupled drive actuated by a magnet (integralto the gyro).dragging, as a high slip eddy current motor, a conductingring which is connected to the rotating erection mechanism. Such speedreduction devices-have disadvantages in that the wear on the high speedgear on the gyro rotor is a limitation on gyro operating life. In thecase of the eddy current motor drive, which is usually associated with aratchet and pawl assembly, a somewhat bulky device results which uses ahigh proportion of available space which might be otherwise better usedfor the gyro ro- I01.

SUMMARY OF THE INVENTION This invention contemplates a dual bearingspeed reducing arrangement wherein the dual bearing has a common raceand separate complementing races and balls so selected that the contactangle of one complement of inner and outer race is different from thecontact angle of the other complement of inner and outer race. If one ofthe separate complementing races is stationary and the common race isoperating at some high speed, the speed of the other separatecomplementing race with relation to the first such race is dependentupon the relative contact angle, which in turn is controlled by theselection of ball sizes. If contact angles for each complementary raceare identical, both separate races have the same speed and if one ofsaid races is stationary the other is likewise stationary. If thecontact angles are different, i.e., one ball complement has balls of aslightly different diameter, than the other one of the separate raceshas a different rotational rate relative to the common race than theother separate race would have for every rotation of a common ballretainer. A gyro rotor is coupled to the bearing as an input member,whereby the erection system rotates in the same direction as the gyrobut at a greatly reduced speed.

One object of this invention is to provide a speed reducing bearingarrangement for rotating a mechanical erection system used with avertical gyro.

Another object of this invention is to provide a speed reducing bearingarrangement including a dual bearing having a common race, a common ballretainer and separate complementing races and balls so selected that thecontact angle of one complement of inner and outer races is differentfrom the contact angle of the other complement of inner and outer races.

Another object of this invention is to achieve speed reduction throughproviding balls of different size in the bearings, whereby changes inthe contact angle of the balls achieves speed reduction.

Another object of this invention is to provide a gyro system of the typehaving a mechanical erection mechanism and including speed reducingmeans for coupling the erection mechanism to the gyro rotor for rotatingsaid mechanism at a speed lower than that of the rotor.

Another object of this invention is to provide a speed reducingarrangement of the type described which is more efficient in operationthan gear train speed reducers or eddy current type drives now known inthe art.

The foregoing and other objects and advantages of the invention willappear more fully hereinafter from a consideration of the detaileddescription which follows, taken together with the accompanying drawingswherein one embodiment of the invention is illustrated by way ofexample. It is to be expressly understood, however, that the drawingsare for illustration purposes only and are not to be construed asdefining the limit of the invention.

DESCRIPTION OF THE DRAWINGS FIG. 1 is a side view of a double bearingspeed reducing arrangement according to the invention.

FIG. 2 is a graphical representation showing the speed reductionachieved by varying ball bearing contact angles.

FIG. 3 is a plan view of the speed reducing arrangement of FIG. Iapplied to a gyro device including a mechanical erection mechanism.

DESCRIPTION OF THE INVENTION The ball bearing speed reducer shown inFIG. 1 includes a bearing 2 having a stationary outer race 4 and aninner race 6, and a bearing 8 having a stationary outer race 10, aninner race 12 and a middle race 14. Races 6 and 12 have a common ballretainer.

Inner race 6 of bearing 2 and inner race 12 of bearing 8 are coupled toa common input shaft or member 16 and have the same rotational speed.Middle race 14 of bearing 8 is coupled to an output shaft or member 18having a speed lower than that of shaft 16 as will be hereinafterexplained.

Inner race 6 and outer race 4 of bearing 2 are coupled to each otherthrough balls 22, and inner race 12 and middle race 14 of bearing 8 arecoupled to each other through balls 23 which are slightly smaller indiameter than balls 22. Middle race 14 and outer race 10 of bearing 8are coupled to each other by balls 24.

Since balls 23 are smaller than balls 22, the contact angles between theballs and the respective races are unequal and the relative velocity ofinner race 6 to outer race 4 of bearing 2 is different than the relativevelocity of inner race 12 to middle race 14 of bearing 8 and middle race14, therefore, has a velocity relative to the velocity of outer race 4.This relative velocity can be varied down to zero by slight changes inthe contact angle of the respective balls in the bearing. As anapproximation, the relative velocity (wR) is given by the followingequation:

R A/ B) 1 (1) where d /d is the ratio of the diameters of balls 22 and23 and m is the relative velocity of inner race 6 to outer race 4 ofbearing 2. It will now be understood that the rotation of middle race 14of bearing 8 can be clockwise or counterclockwise depending upon whichof the balls 22 or 23 have the larger diameter.

With reference to FIG. 2, if the ball (22, 23) diameters are the same sothat the contact angle is, for example, l5.46, the relative speed of thetwo separate races is zero. If the contact angle of the second set ofraces is,

for example, 13, the relative speed of the two races would be 90 rpm asshown in the Figure. Thus, with the contact angles along the horizontalaxis of the graphical representation of FIG. 2 and for a constant 24,000rpm speed of input shaft 2, the speed of output shaft 18 may be plottedas shown.

As aforesaid, the application of the speed reducing bearing of theinvention is particularly suited to a mechanical erection system for avertical gyro. Thus, if the gyro rotor is coupled as an input member anda gyro erection mechanism of a type well known in the art, is coupled asan output member, the arrangement shown in FIG. 1 will cause the ballerection mechanism to rotate in the same direction as the gyro rotor butat a greatly reduced speed and in accordance with the graphicalrepresentation of F 1G. 1.

This arrangement is described with reference to FIG. 3, wherein there isshown a case or can 30 housing a vertical gyro 32. Gyro 32 includes agimbal 34 carrying a conventional type bearing 36 at one end and a dualbearing arrangement 38 according to the invention at the other end. Thebearings support a gyro motor in the gimbal, andwhich motor includes ashaft 40 journaled in the bearings and supporting a rotor 42 surroundedby a stator 44.

Shaft 40 is coupled by conventional means to bearing 38 as an inputmember and a ball erection mechanism 44 of a type well known in theartas coupled as an output member. In accordance with the aforegoingdescription of the invention, erection mechanism 44 rotates in the samedirection as rotor 42, but at a greatly reduced speed.

It will now be seen from the aforegoing description of the inventionthat the device disclosed is more compact in size and more efficient inoperation than gear train speed reducers or eddy current drivespresently known in the art. The invention is particularly suited to amechanically erected vertical gyro which utilizes some means of rotatingshifting masses or rolling balls around the gyro spin axis at arotational speed which is a small fraction of the rotational speed ofthe gyro rotor.

Although but-a single embodiment of the invention has been illustratedand described in detail, it is to be expressly understood that theinvention is not limited thereto. Various changes may also be made inthe design and arrangement of the parts without departing from thespirit and scope of the invention as the same will now be understood bythose skilled in the art.

What is claimed is: 1. A gyro system, comprising:

a gyro motor including a rotor rotating at a predeter mined speed;

mechanical erection mechanism; a bearing assembly coupling the rotor tothe erection mechanism being coupled to the middle race of the secondbearing; and

the inner and outer races of the first bearing coupled through balls ofa predetermined diameter and the inner and middle races of the secondbearing coupled through balls of a diameter slightly smaller than thepredetermined diameter.

I 2. A gyro system, comprising:

a gyro motor including a rotor rotating at a'predetermined speed; i

a mechanical erection mechanism;

a bearing assembly coupling the rotor to the erection mechanism forrotating said mechanism in a predetermined direction and at a speedother than the predetermined speed;

the bearing assembly including a first bearing having an outer race andan inner race, and a second bearing having an outer race, an inner raceand a middle race;

the gyro rotor being coupled to the inner races of the first and secondbearings, and the erection mechanism being coupled to the middle race ofthe second bearing; and 1 the outer races of the first and secondbearings are stationary.

3. Agyro system, comprising;

a gyro motor including a rotor rotating at aipredetermined speed;

a mechanical erection mechanism;

a bearing assemblycoupling the rotor to the erection mechanism forrotating said mechanism in a predetermined direction and at a speedother than the predetermined speed;

the bearing assembly including a first bearing having an outer race andan inner race, and a second bearing having an outer race, an inner raceand a middle race; I

the gyro rotor being coupled to the inner races of the first and secondbearings, and the erection mechanism being coupled to the middle race ofthe second bearing; i

the relative velocity of the inner race to the outer race of the firstbearing is different than the relative velocity of the inner race to themiddle race of the second bearing; and

the middle race of the second bearing has a velocity relative to thevelocity of the outer race of the first bearing.

ll i t i

1. A gyro system, comprising: a gyro motor including a rotor rotating ata predetermined speed; mechanical erection mechanism; a bearing assemblycoupling the rotor to the erection mechanism for rotating said mechanismin a predetermined direction and at a speed other than the predeterminedspeed; the bearing assembly including a first bearing having an outerrace and an inner race and a second bearing having an outer race, aninner race and a middle race; the gyro rotor being coupled to the innerraces of the first and second bearings, and the erection mechanism beingcoupled to the middle race of the second bearing; and the inner andouter races of the first bearing coupled through balls of apredetermined diameter and the inner and middle races of the secondbearing coupled through balls of a diameter slightly smaller than thepredetermined diameter.
 2. A gyro system, comprising: a gyro motorincluding a rotor rotating at a predetermined speed; a mechanicalerection mechanism; a bearing assembly coupling the rotor to theerection mechanism for rotating said mechanism in a predetermineddirection and at a speed other than the predetermined speed; the bearingassembly including a first bearing having an outer race and an innerrace, and a second bearing having an outer race, an inner race and amiddle race; the gyro roTor being coupled to the inner races of thefirst and second bearings, and the erection mechanism being coupled tothe middle race of the second bearing; and the outer races of the firstand second bearings are stationary.
 3. A gyro system, comprising: a gyromotor including a rotor rotating at a predetermined speed; a mechanicalerection mechanism; a bearing assembly coupling the rotor to theerection mechanism for rotating said mechanism in a predetermineddirection and at a speed other than the predetermined speed; the bearingassembly including a first bearing having an outer race and an innerrace, and a second bearing having an outer race, an inner race and amiddle race; the gyro rotor being coupled to the inner races of thefirst and second bearings, and the erection mechanism being coupled tothe middle race of the second bearing; the relative velocity of theinner race to the outer race of the first bearing is different than therelative velocity of the inner race to the middle race of the secondbearing; and the middle race of the second bearing has a velocityrelative to the velocity of the outer race of the first bearing.